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Saturn's Moon Enceladus Has an Atmosphere
Dimentox writes "The Mercury News reports that the international Cassini spacecraft has discovered that Saturn's moon Enceladus has a significant atmosphere, NASA said Wednesday.
The icy moon's atmosphere may be created by volcanism, geysers or gases escaping from the surface or the interior, the space agency's Jet Propulsion Laboratory said.
Excluding Saturn's giant moon Titan, which was already known to have an atmosphere, it's the first discovery of an atmosphere on one of the more than 30 moons that orbit the ringed planet."
but, alas, lacks ambiance. We give it one star.
Excluding Saturn's giant moon Titan, which was already known to have an atmosphere, it's the first discovery of an atmosphere...
Excluding the first it's the first? We have a word for that. "Second".
~Lake
It's really great news for the mission especially after the wind measurement tool didn't function properly at first. 15 more years, and there'll be a space craft at this moon.
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Link It should be noted that this isn't an atmosphere in the common sense. The air is continually created and lost due to internal sources and weak gravity.
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Wired article as proof
Excluding the more than 30 moons that orbit the ringed planet, it's the first discovery of a moon orbiting the ringed planet!
I know this argument is getting old, but this is a good example why we should be spending more money on unmanned probes instead of high-cost, low-science manned missions like the space station. There's little reason at the moment to spend large sums of taxpayer cash on things that provide little benefit. Imagine all the probes we could be sending instead. A whole fleet of Cassinis, Voyagers, and Mars Rovers combing the solar system! Let the private industry (ie. the guys with Scaled Composites and maybe even Virgin ;) take the baton on manned space flight. Hopefully the private industry will find ways to lower the costs so that when we finally need people in space, it'll be practical.
It's right here. Why that page wasn't linked to in the first place is beyond me.
The link says that it's made of water vapor, but doesn't give a density. It's interesting, because Europa (a seemingly similar moon - it has the same sort of wrinkled surface) has a *very* tenative (about 1/100,000,000,000th of 1 atmosphere) water vapor and oxygen atmosphere from the sublimation of ice and the breakdown of water from interaction with the solar wind.
I'd imagine that this atmosphere is notably more significant than Europa's, or they wouldn't have described it as they did. And, with less solar energy at these distances, they're speculating that the source is from internal heating causing water geysers. That's really rather fascinating, when you think of it - now we know of another moon with a likely subsurface sea. The moon is a lot smaller than Europa, but it probably has more significant internal heating for its size.
Plus, the saturnian system has a lot of interesting organics - Titan is virtually a drifting mobile organic chemistry lab in its upper atmosphere. Even neglecting Titan, there's the unknown dark organics on Iapetus, Phoebe, and in the rings, among other places.
"Here's a fun fact: the moon has turned to blood!" -- Newscaster, "Jesus Christ Supercop"
The Mercury News reports that the international Cassini spacecraft has discovered that Saturn's moon Enceladus has a significant atmosphere, NASA said Wednesday.
Not only that, but I bet there's an entire rebel base there as well!
NASA should better send down a probe there to check it out.
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Actually, the Cassini project is a co-op by NASA and the ESA (European Space Agency).
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Wrong moon. You want Mimas.
Show me on the doll where his noodly appendage touched you.
Excluding the posts above, I *finally* have a first post.....
Alternatively, since gravity appears to be insufficient to hold the atmosphere in, if the northern hemisphere's atmosphere and southern hemisphere's atmosphere never interact (eg: there's nothing left of either by the time you reach the equator) then you could again argue that they should be considered distinct and not part of a single whole atmosphere.
Of course, these are highly improbable, but this IS Slashdot.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Europa has H2O in both ice and liquid forms, which is horribly unlikely at near-zero pressure, which means it almost definitely has an atmosphere.
Any comet can be considered as having an atmosphere, whilst it is close to the sun and being frazzled. However, I think there are some who consider that cheating.
Any object close to (or larger than) the size of Mars is going to have an atmosphere, provided at least one of the following conditions is met:
The gas giants can form either from a cloud that coalesces as per a rock planet, but never actually becomes solid, OR when a very large rock planet sweeps enough lighter material to build an atmosphere around it. Jupiter is now thought to be of the first kind, Saturn of the latter.
There may be other ways an atmosphere can form, but these would seem to be a good start on a list.
How can an atmosphere NOT form on a planet?
I don't know what the odds are for any of these, but it would seem reasonable to suppose that 20-30% of all moons will have some sort of atmosphere, and maybe 60-80% of all planets do. We've not found many small extrasolar planets, so we can't tell from that. However, if you go by mechanisms, those percentages feel reasonable enough.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Just in case you actually care. The reason spinning space stations don't work is called coriolis acceleration. Basically spinning results in horizontal as well as vertical acceleration. The vertical is what you want. The horizonal is what disorients and makes astronauts sick. Now, if you happen to have a really really big wheel you can reduce the effects of coriolis acceleration but yeah, you need all that mass. One solution to this is to use a tether and spin a small station around a very very long axis (like kms). That's great an all but 1) it doesn't work in low earth orbit and 2) if the tether breaks you've got a nice uncontrollable projectile there. Then there's the actual problem of getting it spinning in the first place.
How we know is more important than what we know.